The 22-year-old, who the Blades signed from Swedish outfit Helsingborgs
for £1.85million in January 2007, has struggled to force his way into the
first-team picture at Bramall Lane.

United manager Kevin Blackwell said: "Luton wasn't exactly what I was
looking for - he was a bit of a maverick. "This opportunity arose for him
to play regularly and is just what he needs at this stage of his career."

The Jamaica international was restricted to 21 appearances for the
Blades last season, mainly from the substitutes' bench, and scored four
goals.

Shelton will be best remembered for his opening goal in last season's FA
Cup win over Manchester City which deflected in off one of several stray
balloons.